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Double Bass Fuses for amps and preamps

neddyrow

neddyrow

www.simmerinstew.com
Apr 21, 2011
2,309
3,136
Cortland, NY
#1
I've got an acoustic image focus SA and and groove tubes brick that I've had for awhile and I was thinking I should have some backup fuses for them in case they die during a gig or recording session. Is there a pack of fuses that has a varied assortment for guys like me. I was on the internet and it was very confusing finding the ones I needed in a pack. Can someone help me with what would be the smartest way to go about this?
 
#2
neddyrow said:
I've got an acoustic image focus SA and and groove tubes brick that I've had for awhile and I was thinking I should have some backup fuses for them in case they die during a gig or recording session. Is there a pack of fuses that has a varied assortment for guys like me. I was on the internet and it was very confusing finding the ones I needed in a pack. Can someone help me with what would be the smartest way to go about this?
Click to expand...

+1 I have two Walter Woods amplifiers that use different amperage fast blow fuses. When I looked in my amp bag, this weekend I realized that I don't have that little tin of replacement fuses, for either amp. I'd love to know
where to source em. You used to be able to go to car dealership or hardware store where they would have an entire display of Buss fuses, with different amperages.

Ric
 
#3
Parts Express, Mouser, and good old Radio Shack are good sources. There are many others. Be sure to get the proper amperage and latency (e.g., fast-blow, slow-blow).
 
#4
Some of the places mentioned will sell you individual fuses but it is better to have multiple ones anyway so that you have spares. There isn't an assortment that you can buy that will cover all your gear.

Fuses come indifferent sizes and ratings. I think that your best approach is to pull the external fuse and write down all the information such as amperage, voltage, size, a part number, and even the manufacturer. Take a pic if you can. Check that against any labels on the chassis or specs in the manual just in case the wrong fuse has been installed.

I said external fuse above. Some amps also have fuses inside the chassis. Not something that you want to deal with at a gig but something that you might want to be aware of.
 
#5
beans-on-toast said:
Some of the places mentioned will sell you individual fuses but it is better to have multiple ones anyway so that you have spares. There isn't an assortment that you can buy that will cover all your gear.

Fuses come indifferent sizes and ratings. I think that your best approach is to pull the external fuse and write down all the information such as amperage, voltage, size, a part number, and even the manufacturer. Take a pic if you can. Check that against any labels on the chassis or specs in the manual just in case the wrong fuse has been installed.

I said external fuse above. Some amps also have fuses inside the chassis. Not something that you want to deal with at a gig but something that you might want to be aware of.
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It's standard practice for external fuse ratings to be given on the chassis. That's the most reliable source because, as you say, an improper fuse could have been installed. The caps on buss fuses will usually indicate their size. Taking a picture is fine but, hey, they're really small, so they're easy to take along for comparison. Beyond the ratings, the only thing of concern is that you get the correct length fuse. I wouldn't be concerned with writing down the part number or the manufacturer of a buss fuse. They're a dime a dozen and it's the ratings that count. It's not as if we're dealing with semiconductors. It's just not that complicated.:)
 
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#6
Making sure that you know what type of fuse is required isn't a big deal. People that take fuses out of their amps sometimes manage to loose them. Sometimes they loose the fuse holder cap and the fuse. These things can happen. :laugh:
 
#7
Here's the back of the brick ...
ImageUploadedByTalkBass1414540697.067641.jpg


The weird part us that the black part where the fuse goes in says use a 250v fuse.
 
#9
Trust what is on the chassis of the amp you actually have. No need for phone calls. :) With all due respect, you're waaaaaay over-thinking this.

Edit-- Ok, I just checked the Contra manual. It calls for the same fuse as the chassis in your picture. No disparity. Relax. :)
 
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#10
So now you know what values you need 1A slo-blo, 6.3A fast-blo. The 250v rating is normal to use.

Generally there are fast, normal, and slow blow fuses found in amps. There are other types as well. So not all fuses are the same. The manufacturer specified fast blow on the chassis. Fast and ultrafast fuses tend to be found in semiconductor circuits; tube amps often use normal or fast blow.

You just need to look at the fuses to check the size. The Focus SA look like it's a 1-1/4"x 1/4" but you will need to check it.
 
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#11
Wow-- ten posts (now 11) to replace a fuse. Let's sum up. The chassis tells you the rating. You check the physical size. You buy the fuse(s) at one of many potential suppliers. :)
 
#14
I bought a giant collection of various fuses on Ebay about ten years ago for like ten bucks. I dive into it about four times a year for everything from amps/Hi-Fi to lamp dimmers and shop machinery. Money well spent. Go to a big box store and you'll probably pay five bucks for a pair, if they even have what you need.
 
#15
robobass said:
I bought a giant collection of various fuses on Ebay about ten years ago for like ten bucks. I dive into it about four times a year for everything from amps/Hi-Fi to lamp dimmers and shop machinery. Money well spent. Go to a big box store and you'll probably pay five bucks for a pair, if they even have what you need.
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True. Notice that big-box stores weren't included in my recommended sources. :)
 

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